1. Technical Field
The present disclosure relates to touch panels and liquid crystal display screens and, particularly, to a carbon nanotube based touch panel, a liquid crystal display screen using the same, and methods for making the touch panel and the liquid crystal display screen.
2. Description of Related Art
Liquid crystal display screens are relatively thin, light weight, have low power consumption. Liquid crystal display screens have been widely used in various electronic apparatuses having displaying functions such as computers and televisions as well as on portable devices such as mobile phones, car navigation systems, and personal digital assistants (PDAs).
Following the advancement in recent years of various electronic apparatuses, toward high performance and diversification, there has been continuous growth in the number of electronic apparatuses equipped with optically transparent touch panels in front of their respective liquid crystal display screens. A user of any such electronic apparatus operates it by pressing or touching the touch panel with a finger, a pen, a stylus, or another like tool while visually observing the display of the liquid crystal display screen through the touch panel. Therefore, a demand exists for touch panels and liquid crystal display screens using the same that provide superior in visibility and reliable operation.
Up to the present time, different types of touch panels, including resistance, capacitance, infrared, and surface sound-wave types have been developed. Due to their higher accuracy and low-cost of production, the resistance-type touch panels have been widely used.
Typical resistance-type touch panel includes an upper substrate and a lower substrate. The upper substrate includes an optically transparent upper conductive layer and two upper electrodes connected to the optically transparent upper conductive layer at two edges along the X direction respectively. The lower substrate includes an optically transparent lower conductive layer and two lower electrodes connected to the optically transparent upper conductive layer at two edges along the Y direction respectively. The upper substrate is a transparent and flexible film or plate. The lower substrate is a transparent and rigid plate made of glass. The optically transparent upper conductive layer and the optically transparent lower conductive layer are formed of conductive indium tin oxide (ITO). The upper electrodes and the lower electrodes are formed by silver paste layers.
In operation, an upper surface of the upper substrate is pressed with a finger, a pen or the like tool, and visual observation of a screen on the display device provided on a back side of the touch panel is allowed. This causes the upper substrate to be deformed, and the upper conductive layer thus comes in contact with the lower conductive layer at the position where pressing occurs. Voltages are applied successively from an electronic circuit to the optically transparent upper conductive layer and the optically transparent lower conductive layer. Thus, the deformed position can be detected by the electronic circuit.
However, the ITO layer generally has poor mechanical durability, low chemical endurance, and provides for uneven resistance over an entire area of the touch panel. Moreover, the ITO layer has relatively low transparency in a humid environment. All the above-mentioned problems of the ITO layer tend to yield a touch panel with somewhat low sensitivity, accuracy, and brightness. Furthermore, the ITO layer is generally formed by means of ion-beam sputtering, and this method is relatively complicated.
What is needed, therefore, is to provide a touch panel, a liquid crystal display screen using the same, and methods for making the touch panel and the liquid crystal display, the touch panel and the liquid crystal display screen having good durability, high sensitivity, accuracy, and brightness to overcome the aforementioned shortcomings.
Corresponding reference characters indicate corresponding parts throughout the several views. The exemplifications set out herein illustrate at least one embodiment of the present touch panel, the liquid crystal display screen using the same, and the method for making the touch panel and the liquid crystal display screen in at least one form, and such exemplifications are not to be construed as limiting the scope of the invention in any manner.